Magnetic Resonance Imaging Apparatus and Image Processing Method

1. A magnetic resonance imaging apparatus, comprising: an imager having a plurality of receiving coils and configured to collect nuclear magnetic resonance signals from a subject; and an image processor configured to reconstruct an image of the subject using the nuclear magnetic resonance signals collected by the imager, wherein the image processor comprises an image separator configured to separate a phase of a low-resolution image reconstructed from the nuclear magnetic resonance signals obtained by each of the plurality of receiving coils, and a phase of a main captured image that is reconstructed from the nuclear magnetic resonance signals obtained by the plurality of receiving coils, and superimposed with a plurality of images, to separate the plurality of images included in the main captured image, wherein the main captured image is an image, that is obtained by simultaneously collecting the nuclear magnetic resonance signals from a plurality of cross-sections of the subject by the imager, and superimposed with a plurality of cross-sectional images, wherein the image separator is configured to calculate a phase of each cross-sectional image from the phase of the low-resolution image obtained from each of the plurality of receiving coils for the plurality of cross-sections, and to use the phase of each calculated cross-sectional image, and a signal intensity and the phase of the main captured image, to calculate the signal intensity of each cross-sectional image.

2. The magnetic resonance imaging apparatus according to claim 1 , wherein the low-resolution image is an image obtained by pre-scan by the imager.

3. The magnetic resonance imaging apparatus according to claim 1 , wherein the low-resolution image is a reception sensitivity distribution image of the plurality of receiving coils.

4. The magnetic resonance imaging apparatus according to claim 1 , wherein the main captured image is an image obtained by performing undersampled aquisition of data in a phase encoding direction by the imager.

5. The magnetic resonance imaging apparatus according to claim 1 , wherein the main captured image is superimposed with an image in a field of view and an image aliased from outside the field of view.

6. The magnetic resonance imaging apparatus according to claim 5 , wherein the image separator is configured to use a phase of the image in the field of view calculated from the phase of the low-resolution image obtained from each of the plurality of receiving coils, and a signal intensity and the phase of the main captured image, to calculate the signal intensity of the image in the field of view.

7. The magnetic resonance imaging apparatus according to claim 1 , wherein the image processor further comprises a noise amplifier configured to permit evaluation of noise amplification during image separation by the image separator.

8. A magnetic resonance imaging apparatus, comprising: an imager having a plurality of receiving coils and configured to collect nuclear magnetic resonance signals from a subject; and an image processor configured to reconstruct an image of the subject using the nuclear magnetic resonance signals collected by the imager, wherein the image processor comprises an image separator configured to separate a phase of a low-resolution image reconstructed from the nuclear magnetic resonance signals obtained by each of the plurality of receiving coils, and a phase of a main captured image that is reconstructed from the nuclear magnetic resonance signals obtained by the plurality of receiving coils, and superimposed with a plurality of images, to separate the plurality of images included in the main captured image, wherein the image processor further comprises a noise amplifier configured to permit evaluation of noise amplification during image separation by the image separator, and wherein the noise amplifier is configured to optimize the phase of the low-resolution image so as to minimize the noise amplification.

9. An image processing method for separating a true image from a measurement image obtained by magnetic resonance imaging and superimposed with a plurality of images including the true image, comprising: a step (1) of calculating a phase of the true image using a low-resolution image; and a step (2) of calculating a pixel value of the true image using a calculated phase of the true image and a phase and a pixel value of the measurement image, wherein the step (2) comprises a step of optimizing a phase of the low-resolution image so as to minimize noise amplification.

10. The image processing method according to claim 9 , wherein the measurement image is an image obtained by undersampled imaging using a plurality of receiving coils, and in the step (1), the phase of the true image is calculated using a phase of the low-resolution image obtained for each of the plurality of receiving coils.

11. The image processing method according to claim 9 , wherein the measurement image is an image reconstructed from nuclear magnetic resonance signals simultaneously collected by simultaneously exciting a plurality of cross-sections of a subject, and the low-resolution image is an image obtained by individually imaging the plurality of cross-sections.